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Heater bees

The thing that jumps out at me is how this concept runs directly counter to what we've all read in just about every beekeeping book there is about the progression of responsibility of an individual bee throughout its lifetime.

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The secret of honey bees' success has been discovered living deep inside their hives - a special type of bee which acts like a living radiator, warming the nest and controlling the colony's complex social structure.

The "heater bees" have been found to play a crucial, and previously unappreciated, role in the survival of honey bee colonies.

Using new technology that allows sceintists to see the temperature inside the bee hives, researchers have been able to see how heater bees use their own bodies to provide a unique form of central heating within a hive.

They have found that these specialised bees, whose body temperatures are considerably higher than other bees in the colony, not only keep the hive warm but also control the social make-up within a colony.

Bees, and other social insects such as ants, share jobs within a colony so each individual has specific role that benefits the colony as a whole.

It is this division of labour that has allowed bees to become so successful as they behave like a highly organised, single "superorganism" rather than a cluster of selfish individuals.

Heater bees are responsible for maintaining the temperature of the brood nest in a hive, where young bees, known as pupae, are sealed into wax cells while they develop into mature bees.

The scientists discovered that the heater bees work to subtly change the temperature of each developing pupae by around a degree and this small change determines what kind of honey bee it will become.

Those kept at 35 degrees C turn into the intelligent forager bees that leave the nest in search of nectar and pollen.

Those kept at 34 degrees C emerge as "house keeper" bees, conducting chores such as feeding the larvae and cleaning the nest.

Professor Jürgen Tautz, head of the bee group at Würzburg University, in Germany, said this allows the heater bees to control what sort of job a bee will fulfil when it matures and so ensure there are always enough bees filling each role within the colony.

He said: "The bees are controlling the environment they live in to make sure they can fill a need within the colony.

"Each bee in a colony performs a different profession – there are guard bees, nest building bees, brood caretaking bee, queen caretaking bee and forager bees, which are the ones we are familiar with as they leave the colony.

"By carefully regulating the temperature of each pupae, they change the way it develops and the likelihood of the role it will fulfil when it emerges as an adult."

The findings will be revealed later this month in a new BBC series Richard Hammond's Invisible World, where technology is used to give a glimpse into previously unseen worlds.

Thermal imaging cameras reveal how individual heater bees warm up the nest to precisely the right temperature.

By beating the muscles that would normally power their wings, heater bees increase the temperature of their bodies up to 44 degrees C – nearly 10 degrees hotter than a normal bee.

They then crawl into empty cells within the brood nest, transmitting heat to the surrounding cells where the bee pupae are developing. The waxy cells also help circulate the heat around the rest of the hive.

In the past beekeepers have seen these empty cells as undesirable and have attempted to breed queens that did not leave them empty, but Professor Tautz now claims they are an essential part of ensuring the health of a bee colony.

Warmth is essential for bees as they need a body temperature of around 35 degrees C to be able to fly.

The heater bees, which can number from just a few to many hundreds depending on the outside temperature and size of the hive, also press themselves against individual cells to top up the temperature of each pupae to ensure it develops into the right kind of bee.

Professor Tautz added: "The old idea was that the pupae in the brood nest were producing the heat and bees moved in there to keep warm, but what we have seen is that there are adult bees who are responsible to maintaining the temperature.

"They decouple their wings so the muscles run at full power without moving the wings and this allows them to raise their body temperature extremely high.

"Their body temperature can reach up to 44 degrees centigrade. In theory they should cook themselves at that temperature, but somehow they are able to withstand this high temperature.

"By creeping into empty cells, one heater bee can transmit heat to 70 pupae around them. It is a central heating system for the colony.

"Now we know that these empty cells are important, then bee keepers can try to avoid selecting for queens that don't leave these cells empty. It can help to ensure that colonies can regulate their temperature properly and have the right mix of individuals."

Temperature is known to have an influence on the development of young in other animal species.

In crocodiles, the sex of hatchlings is determined by the average temperature of the eggs during a key point in the incubation period, so if they are kept above 34.5 degrees C the offspring will be male.

Many species of fish and turtles also use temperature to determine the sex of their young.

Dr David Aston, chair of the British Beekeepers Association's technical and environmental committee, said: "There has never been a good reason for the presence of individual empty cells across the face of the comb.

"Now Professor Tautz has provided an explanation and beekeepers will look more closely at the brood combs to see if they can observe heater bees at work."

Richard Hammond's Invisible World will begin on BBC One on March 16. The episode with the heater bees will be shown on March 23.

Professor Tautz has asked us to make clear that the temperature changes brought about by the heater bees alter the probablity of the tasks that will be performed by larvae when they mature.

Readers wishing to study for themselves the effects of different brood temperatures on the life of individual bees can visit the researchers website.
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Re: Heater bees

I just finished reading "The Buzz about Bees" by Jurgen Tautz and I highly recommend it. The information about heater bees was fascinating and I learned many things from this book that I had never heard of in the other bee books I have read.

Re: Heater bees

I guess my observation hive dosent have enuf heater bees because all the hours ive spent watching it every single bee i have wached chew there way out of a cell imediatly start cleaning out cells, not foraging.........I dont know how they managed to gather so much honey and pollen.

I knew that it was the adult bees that generated the heat, never read anything claiming that the brood generates its own heat.

I just find it easyer to believe that pheromones delegate the different jobs of the hive, not the temp that the brood is kept at.

If that was true wouldnt that mean that during really hot summers if there werent enuf cooler bees they wouldnt be able to raise anything but foragers with none left to raise the brood?

Re: Heater bees

Originally Posted by WiredForStereo

I may have missed something, but I don't see where it says that.

Professor Tautz added: "The old idea was that the pupae in the brood nest were producing the heat and bees moved in there to keep warm, but what we have seen is that there are adult bees who are responsible to maintaining the temperature.

what I meant was I didnt know that was the old idea.....I guess Im not old enuf.

Re: Heater bees

That's pretty interesting. I've always wondered if there was a stage in a bees life that they were "defender" bees. But if temp controls what they become - If you could find out if defender bees were held at a certain temp during the pupae stage - maybe you could identify which hives would be more aggressive. Maybe you could identify Africanized Colonies with a thermal gun.

Re: Heater bees

Originally Posted by Jpoindexter

That's pretty interesting. I've always wondered if there was a stage in a bees life that they were "defender" bees. But if temp controls what they become - If you could find out if defender bees were held at a certain temp during the pupae stage - maybe you could identify which hives would be more aggressive. Maybe you could identify Africanized Colonies with a thermal gun.

Very interesting hypothesis. Perhaps there is a connection with Africans and the cold as well.

Re: Heater bees

I had seen that information elsewhere, and it makes fascinating reading. What I suspect is that new technologies are enabling us to discover that the honeybee (and many other organisms as well) are much more complex than we realize. It is an exciting time to be a beekeeper!

I further suspect that, the more they study the "heater bee" phenomenon, they'll discover this is simply one more piece to the puzzle of how bees divide tasks in the hive. If the only differentiation is determined in the pupal stage, isn't the colony doomed when it's circumstances change? I don't know that we can, as yet, throw out the idea that bees move through hive tasks as they age - from housekeeping to forager, for instance. That, coupled with the needs of the colony also. I suspect we'll find out it is much more complex than simply either/or. Either heater bees determine tasks of other bees in the pupal stage, OR they don't - the bee moves through a progession of tasks as it ages.

What the heater bee studies definitely do, however, is shed much more light on how the winter cluster functions, and how they keep brood alive in cold temperatures.
Regards,
Steven

"If all you have is a hammer, the whole world is a nail." - A.H. Maslow

Re: Heater bees

Yes there is some plasticity in bee behavior, and for a good reason, it allows the hive adaptable to changing circumstances. Temperature during development clearly drives some elements of bee behavior but not all.

This is only one part of the puzzle. We have discussed in this forum before about developmental temps and learning and memory.

I have read that an individual bee can heat up to a max of 107 degrees.

Re: Heater bees

In the middle of the day, move a hive some distance away, and in it's place put an empty hive with a comb of eggs in it, no bees.

The bees returning to it are all foragers, right?

In fact, they will adapt to what's needed. The brood will be fed and cared for, which involves royal jelly making. New comb will be built, which involves wax making. A new queen will be raised, the hive will be cleaned, the hive will be gaurded, the hive will be ventilated etc....

Re: Heater bees

Oldtimers post make the case for plasticity of behavior. In that scenario field bees would have to revert to nurse bees, heater bees, etc.

The studies on incubation temperature influences on learning and memory are solid and fascinating. One could see where diminished populations that have more brood area than they could properly heat would be in trouble.

Re: Heater bees

During the cool days of early spring, you will find drones in the insulative outer layer of the cluster around it and over it. The big boys act a natural heating unit providing extra warmth with their extra volume to the inner cluster. TK

Re: Heater bees

Nobody seems to be questioning an assertion that I always felt was a given and that is that young bees are first nurse bees and when they are more fully mature become foragers. I aware that as Oldtimer states when needed bees can serve whatever function is most critical for the survival of the hive.

"People will generally accept facts as truth only if the facts agree with what they already believe."- Andy Rooney

Re: Heater bees

Heater bees makes sense to me and would explain some observations.
Die-outs, heads in cells means starving, with food right there? Maybe cluster was too small to keep warm (from varroa most likely) and bees died trying to keep that last bit of warmth going. Not all the bees, but some of those bees could possibley have been heater bees, in my mind. Another thing, in spring with cooler temps and more variance in temps I see more spotty brood pattern, perhaps for room for heater bees? Because a month or two later as temps stabilize, the brood pattern gets solid... no need for heater bees? These are my thoughts as I was reading that book.

Re: Heater bees

Ray's comments got me thinking... Consider the dead clusters we've seen. The number of bees in the center, head into the cell, and bees stacked on top of them. One heater bee head into a cell would not only warm bees above her, but how many cells around her and on both sides of the central membrane of the comb would she heat? Quite a few I imagine. So the head-in bees in the center of the dead cluster were heating and conserving heat and space... head-in bees elsewhere and solitary bees elsewhere were foraging for honey to keep the colony alive? So as the fuel, the honey, becomes more scarce and harder to retrieve, the further the bees have to travel to get it and chill and die in the process, the cooler the heater bees get, the cooler the cluster gets, and you have a downward spiral to death.
Regards,
Steven

"If all you have is a hammer, the whole world is a nail." - A.H. Maslow

Re: Heater bees

I find it very interesting reading, and I believe that the study may be onto something. Especially the way they warm the cluster. But until more than one unproven study can show that the "heater bee" can or does control what jobs the population of the hive does, I think I will still subscribe to the age old theory that as they mature they progress in the jobs they do.